Thomassen, B., T. Tukiainen, and K. Secher. “Detailed Investigation of the Niobium-Tantalum Distribution Within the Motzfeldt Centre, South Greenland”. Rapport Grønlands Geologiske Undersøgelse, vol. 140, Dec. 1988, pp. 66-70, doi:10.34194/rapggu.v140.8038.